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When to Plant Mitsuba in USDA Zone 4b

Mitsuba (Japanese parsley) is a shade-loving herb with trefoil leaves and a mild celery-parsley flavor. It is essential in Japanese cuisine for soups, salads, and garnishes.

In Zone 4b, the average last spring frost is around May 1 and the first fall frost is around October 3, giving you a growing season of approximately 155 days.

Zone 4b Moderate season
155 days
Last Spring Frost May 1
155 growing days
First Fall Frost October 3

Mitsuba Planting Timeline — Zone 4b

Where Is USDA Zone 4b?

The map below highlights the states that contain Zone 4b. Click any state to see the Mitsuba planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Mitsuba Planting Calendar — Zone 4b

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors April 24 Apr 24 – May 8
Direct Sow April 24 Apr 24 – May 15
Fall Sowing July 11 Jul 11 – Jul 25
Harvest June 19 Jun 19 – Aug 14

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December

Free Zone 4b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 4b with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate — regular watering

Days to Maturity

50–70 days

Soil pH

6 – 7

Zone Temperature Range

-25°F to -20°F average annual minimum

Growing Season

155 days (Zone 4b average)

Planting Specifications

Planting Depth0.5 inches
Plant Spacing8 inches apart
Row Spacing12 inches between rows

Growing Tips for Zone 4b

Direct sow or start indoors in partial shade. Mitsuba prefers cool, moist conditions. Harvest outer stems as needed. Self-sows readily in shaded garden areas.

Companion Planting

Good Companions

Level Up Your Garden

Saving Mitsuba Seeds

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Protect plants from frost, wind, and pests while letting light and water through.

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Frequently Asked Questions

When should I plant Mitsuba in Zone 4b?

In Zone 4b, plan your Mitsuba planting around the average last frost date of May 1. Start seeds indoors around March 20. Direct sow outdoors around April 24. Transplant seedlings around April 24.

Can Mitsuba grow in Zone 4b?

Yes, Mitsuba can grow well in Zone 4b, hardy in USDA zones 4a through 9b. Zone 4b has a growing season of approximately 155 days, which is sufficient for Mitsuba (50-70 days to maturity).

When can I harvest Mitsuba in Zone 4b?

In Zone 4b, expect to harvest Mitsuba from June 19 – August 14. Mitsuba takes 50-70 days from planting to harvest.

What is the last frost date for Zone 4b?

The average last spring frost in Zone 4b is around May 1, and the first fall frost is around October 3. This gives a growing season of approximately 155 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Mitsuba?

Good companion plants for Mitsuba include Lettuce, Spinach. These companions can help with pest control, pollination, and nutrient sharing.

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Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 4b, track your crops, and plan your garden season from seed to harvest.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.